The known door locking and securing mechanisms, which constitute the prior art and are typically used in the doors of medical devices, sterilizers or laboratory apparatuses, are usually conceived as linkage-type mechanisms.
A known door closing mechanism is operated by means of a handle that is rigidly coupled with hooks. The axis of rotation of the hooks is identical to that of the handle. The movement of the handle causes the hooks to be driven in rotation. Once the mutual engagement of the hooks and the fixed part of the closing mechanism, which is attached to a cabinet, is achieved, the continuing movement of the handle causes the door to start moving towards the cabinet. The movement of the door, however, is accompanied by the friction between the hooks and the fixed part of the closing mechanism. The frictional force is inversely proportional to the distance between the door and the cabinet at any given moment. The above effect hinders the door from being closed or opened in a convenient manner. Moreover, it is often accompanied with undesirable acoustic emissions.
The U.S. Pat. No. 8,403,380 B2 discloses a cover closure for housing cover of laboratory and the like, in particular for centrifuge housings, in which a cover hook is engaged by a closure hook and brought into a closing position. The closing and opening movement of the closure hook is essentially caused by an eccentric in connection with a crank guide and a guide path.
The U.S. Pat. No. 2,128,014 A discloses a door lock enabling the door to be opened and closed from the inside at any time, whereas to be opened from the outside only upon having last been closed from outside. According to one of its embodiment, the door lock comprises two lock handles concentrically mounted on each other in such manner that the outer handle (pointing outwards) is movable on the spindle of the inner handle (pointing inwards). The apparatus further comprises a lock bolt displaceably attached to a disc by means of two pins secured on the disc, projecting into a slit in the bolt. The disc is rotatably mounted on the spindle of the handle and the bolt is provided with a transverse recess to engage with a contact flap for locking. There is a helical spring inserted between the disc and the bolt forcing the bolt outwardly in the closing phase and another helical spring returning the inner handle into its initial opened position. The presence of two handles requires additional features to be included in the movement of the locking mechanism, namely a lever, a pawl and a plurality of pins. By rotating the outer handle, the movement of the bolt towards the contact flap is translational and delimited by two pins secured on the disc. The bolt 12 slides against the pins 40, 41 which are not located on the rotational axis of the outer handle 9. Furthermore, the transverse recess merely inserts itself in the contact flap, it is not secured by a hooking movement. By rotating the inner handle, the movement of the bolt towards the contact flap is circular, not along a curved trajectory, thereby hooking the transverse recess of the bolt in the contact flap. However, the hooking movement does not produce any backward movement of the transverse recess or pull of the door towards the door frame.